Acinetobacter glutaminase-asparaginase has been purified, treated with succinic anhydride, tested for sterility, pyrogen activity and biochemical properties. Children with cancer refractory to all conventional chemotherapy have been treated with daily doses of 200-2000 IU/m squared for periods up to 60 days. The enzyme preparation had a half life of 27 plus or minus 7 hours. Antileukemic activity (decrease in blast count of greater than 1 Log) was seen in approximately 50 percent of the patients. Toxicity included nausea, vomiting, weight loss, hyperglycemia, myelosuppression and hypoproteinemia. Five patients became comatose. No patients had pancreatitis or renal abnormalities. No anaphylactic reactions occurred. Currently the nutritional effects of this therapy are being evaluated.